Crab apple looking a bit poorly

Hello folks! I planted a young crab apple at Easter and I think its beginning to look a bit poorly.... some leaves are turning yellow and some are curling up a little. The new shoots seem to be being eaten. I know i have some type of leaf miner moth and thats nothing to worry about, and the trunk looks ok. Not sure if I should be watering with all this rain? This is the first tree I've planted so I'm a novice and really hope I'm being paranoid! What do you think? Thank you for any advice.